Screw-shell-contact mounting for attachment-plugs



E. H. FREEMAN.

SCREW SHELL CONTACT MOUNTING FOR ATTACHMENT PLUGS.

APPLICATION FILED JULY 21, i919- 1,373,127. Patented Mar. 29, 1921.

314 uemtoi UNITED STATES Pa EN'r OFFICE.

- EDAB H. FREEMAN, OF TRENTON, NEW JERSEY, ASSIGNOB TO E. E. FREEMAN ELIETBIC GO HPANY, A CORPORATION 01 NEW JERSEY.

Specification of Letter: Patent;

Patented Mar. 29, 1921.

Application filed July 81, .1918. Serial No. 812,288.

To all whom it may concern Be it known that I, EDGAR H. FREEMAN, citizen of the United States, residin at Trenton, in the county of Mercer and tate of New Jersey, have invented certain new and useful Im rovements in Screw-Shell- Contact Mountings for Attaclnnent-Plugs, of which the following is a specification.

This invention relates to electric fittings and has special reference to an improvement in attachment lugs.

A primary 0 ject of the invention is to provide a simple and practical means for holding the several electrical contact parts of the plug securely'in position. That is to say, the present invention proposes to rovide a construction whereby the screw s ell contact of the lug and one of the spring contact terniina s thereof may be easily and uickly assembled and secured in position. l n this connection it is proposed to provide an arrangement of parts which permits of the fastening means being located at a point where the same will not engage with the screw shell of the lamp socket or equivalent fittin into which the plu is inserted, thereby e iminating danger o the fastening becoming loosened, while at the same time materially enhancing the general structural features of the plug from a practical and serviceable standpoint.

With the above and other'objects in view which will more readily appear as the description of the invention progresses, the same consists in the novel construction shown in the accompanying drawings, in which v Figure 1 is a vertical sectional view of a plug embodying the present improvements.

Fig. 2 is a vertical sectional view taken at right angles to Fig. 1.

Fig. 3 is a perspective View showing the parts prior to assembly.

Similar references desi ing parts throughout the several figures of the drawings. a

The present improvements are susceptible of embodiment in attachment plugs of the usual type which include a plug body. 1 and a detachable contact carrying cap member 2. In this respect the invention involves no departure from the general type of devices of the class to whichit belongs. .The said plug body 1 is however, preferably prognate correspondvided with the longitudinal openings 3 and .a central upstanding knob portion 6 which is countersunk as at 7 to receive the head of a fastening screw 8 that extends through the opening 9 in the axis of the body to receive a holding nut 10 located in the recess 11, for the purpose of securing the center contact member 12 to the plug body. The spring body portion of the center contact member 12 is preferably arranged in the opening 4 of the body as shown in Fig. 1, and the end fastened by the screw 8 constitutes one of the plug terminals for engaging with the center lug contact of the lamp socket or e uiva ent electrical fitting into which the p ug is inserted.

The novel and distinctive feature of the present invention resides in the manner of securing the screw shell contact member 13 and the plug terminal 14 in position, and to this end it is proposed to provide the rim of the plug body surrounding the knob 6 at diametrically opposite points with the tubular rivets or equivalent fastenings 15, the same being preferably molded in the plug body at the time of manufacture. The screw shell 13 is provided with the ear portions 13 for engaging-over the rivets 15, and because of the s acing and arrangement of the latter it wil be ap arent that relative rotation between the shell and the plug body is prevented, the twisting strain or torque being readily absorbed by the two rivets and distributed 1n such a manner as to be efiectively neutralized.

After the perforated ears of the screw shell contact have been fitted over the rivets, the perforated portions 14 at the extremi' ties of the horseshoe-shaped portion of the terminal 1 1 are also placed over the rivets, whereby when the upper ends thereof are upset by spinning, mashing or an equivalent operation, the shell 13 and terminal 14 will be rigidly secured to the plug body, and also to each other thereby establishin a positive electrical contact between the s ell and the terminal in a safe and practical manner.

By reason of the rivets being firmly anchored in the plug body 1, the same constitute in effect a rigid part of the plug itself, and thus are of maximum efiiciency as holding elements for the shell 13 and terminal14 when flanged or headed in the welling in the plug body is to rovide a conknown manner. Furthermore, owing to the verging guid'ewa between t e spring strip fact that these rivets are located at the end and the walls 0 the plug body whlch are of the plug they greatly facihtate the asenga ed by the blades 55,. and because the sembling of the shell.w1th reference to the angu arly disposed ti portion z abuts with plug body and the horseshoe terminal elethe opposite wall of tiie passageway, greater ment wit reference to the shell, and when stlfi'ness is imparted to the sprlng body the plug is inserted in a receptacle the which has the effect of rendering the enflan ed ends thereof will not in any way gagement of the holdin boss y with the bin er the engagement between the plug openin or equivalent eeper elements 5 and the receptacle because of the fact that in the blades more positive to prevent accithe said flanged ends will lie in the space dental withdrawal of the said blades. In between the end of the center contact and other words the intermediate portion of the the plane of the shoulder or rim of the plug spring strip which carries the holding boss body, which space is necessary for insulathas a greater locking effect by reason of ing pur oses. the abutment of the tip portion 2 with the For tie purpose of providing additional wall of the o ening as described, so that a union between the plug body and the shell, relatively lig t s ring strip will have the the same may be provided with the circumsame holding e ect as a strip of much ferential groove G whereby the edge 13 heavier gage. of the shellmay be pressed therein b spin- Without further description it is thought ning or a like operation. This ad itional that the many features and advantages of engagement between the shell and the plug the present invention will be readily apparbod has the effect of stabilizing the relaant, and it will also be understood that tive y thin metal shell 13 on the body and various changes in the form, proportion, provides a neat and attractive finish beand minor details of construction may be .tween the shell and the body adjacent the resorted to without departing from the ca end of the latter. spirit of the invention or scope of the apl rom the foregoin it will be apparent pended claim. that the distinctive f eature of the present I claim invention resides in the provision of an- In an attachment plug, means for uniting chors carried by the plug body parallel to the ca and body includin in combination the axis for the purpose of facilltating the with t e body having para lel blade receivassembly of the screw shell contact and one ing openings therein, of spring contact of the plug terminals for securing the same members mounted 1n each openln and obin position. l quely disposed therein whereby t eir rela- Another novel feature of the present intively free ends engage the outer sides of vention is found in connection with the plug the opening, said springs also having a terminal contact members 12 and 14. The holding portion disposed toward the inner .body1 portion of each contact is preferably wall of the opening, and a cap carrying a in t e form of a flat s ring strip m, ropair of spaced contact members adapted to vided with the pressec -out hol ing oss slidably engage the inner walls of the open- 3/ and ada ted to be so mounted on the plug ings in the body and having keeper eleas to be obliquely disposed in the openings ments for receiving the holding portions 3 or 4. The relatively free end of the flat of the springs.

s )ring strip is provided with the angularly In testimon whereof I hereunto afiix my (ISPOSBd tip portion 2 which is adapted to signature in tie resence of two witnesses. engage wit the wall of the opening oppo- E GAR H. FREEMAN. site that engaged by the base of the sprmg Witnesses:

stri The effect of this oblique disposition OLIVE V. DowNs,

of t e sprlng strip in a passageway or open- ELLEN J. LARRABEE. 

